John Edmond Costello, 52, British historian and author who used unusual access to U.S. and Soviet intelligence files to recast chronicles of World War II and the Cold War. Particularly critical of the British military for refusing to release secret papers, Costello collaborated with KGB deputy spokesman Oleg Tsarev on the 1993 book "Deadly Illusions," the first history of Soviet spying produced with direct access to KGB archives. The book was about Soviet spy chief Alexander Orlov, who recruited the so-called Cambridge spy ring of Britons Kim Philby, Guy Burgess and Donald Maclean. Costello's 1991 book "10 Days to Destiny" detailed the secret story behind abortive German peace feelers that swirled over London in 1940 and 1941 after the fall of France. Costello also wrote histories of the war in the Atlantic and the Pacific and the international competition to develop the supersonic Concorde. He had been researching a book on the wartime friendship of Winston Churchill and Franklin D. Roosevelt. On Aug. 26 in Miami of undetermined natural causes.